Many semiconductor devices comprising integrated circuits have an ESD protection structure monolithically integrated within the semiconductor substrate. For instance, in the field of automotive applications, transceiver ICs for Control Area Network (CAN) communication may comprise monolithically integrated ESD protection structures.
Known ESD protection structures comprise monolithically integrated back-to-back Zener or avalanche diodes. For instance, U.S. Pat. No. 6,642,550 B1 describes a sub-mount for use in a light emitting diode (LED). The sub-mount comprises an ESD protection structure in the form of two back-to-back Zener diodes, which are monolithically integrated into the semiconductor substrate of the sub-mount. A first Zener diode is formed by a pn-junction between a n+-type sinker and a p-type substrate region. A second Zener diode is formed by the junction between the p-type substrate region and an underlying n+-type substrate region extending to a bottom substrate-side of the semiconductor substrate.
A disadvantage of this structure is that it does not withstand high-voltage ESD pulses that are for instance to be used in ESD stress tests (“gun tests”) of semiconductor devices connected to voltage sources of more than 40 Volt. An ESD stress test according to the standard IEC61004-2 uses a short initial high-current pulse with a rise time (10 to 90% of peak amplitude) of between 0.7 and 1 Nanosecond.
It would be desirable to improve a semiconductor device to allow providing an ESD protection with both, a high reverse trigger voltage and fast switching characteristics to reduce the occurrence of device failure do to electrostatic discharge.